It is customary in many business environments for an organisation to provide each employee with a credential device, usually in the form of a card, badge, fob, tag or the like, that can be easily carried or worn by the employee. The credential device typically includes some form of machine readable code, and may also include some form of visual identification. The credential device can be used to enable the employee to gain access to controlled commercial resources and facilities. For example, it is common for commercial premises to have doors with access control responsive to the machine readable codes of credential devices issued by the company. Such systems provide the employer organisation with a high degree of flexibility in access control, but generally require the employees to carry their credential device with them throughout the day.
Modern credential devices are frequently of the type known as ‘proximity cards’ or ‘proximity devices’. Proximity devices are widely used in a variety of applications such as to control access to commercial facilities. In this type of application, a user positions the proximity device proximate to a detector circuit. The detector circuit reads the identification code of the proximity device by way of radio-frequency signals in order to determine the identity of the user. If the user is authorized to gain access, the detector circuit actuates a door lock mechanism. If the user is not authorized, the detector circuit will deny access. Proximity devices make the access control functions relatively convenient for the employees, in fact somewhat more convenient than conventional alternatives such as a traditional key or set of keys.
Throughout the course of a working day it is usual for an employee to carry their personal credential device with them constantly for use at controlled doors into and within the commercial premises, elevators, parking lots and other facilities. For ease of use the credential device may be carried on a lanyard, or clipped or otherwise attached to the user's clothing, by way of example. Thus, during the working day the credential device is one item, above all others, that may employees would have with them at all times.